linux-kernel - Re: [PATCH 1/7] soc: renesas: r9a06g032-sysctrl: Export function to get H2MODE from CFG

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Message-ID: <20221110090217.4f4f4a0e@bootlin.com>
Date:   Thu, 10 Nov 2022 09:02:17 +0100
From:   Herve Codina <herve.codina@...tlin.com>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Magnus Damm <magnus.damm@...il.com>,
        Gareth Williams <gareth.williams.jx@...esas.com>,
        linux-renesas-soc@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-usb@...r.kernel.org,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>
Subject: Re: [PATCH 1/7] soc: renesas: r9a06g032-sysctrl: Export function to
 get H2MODE from CFG_USB register

Hi Geert,

Oops, my bad I removed all people from the email previously.
Re-added them on this reply. 

On Mon, 7 Nov 2022 20:23:06 +0100
Geert Uytterhoeven <geert@...ux-m68k.org> wrote:

> Hi Hervé,
> 
> On Mon, Nov 7, 2022 at 5:54 PM Herve Codina <herve.codina@...tlin.com> wrote:
> > On Mon, 7 Nov 2022 15:40:53 +0100
> > Geert Uytterhoeven <geert@...ux-m68k.org> wrote:  
> > > On Mon, Nov 7, 2022 at 2:59 PM Herve Codina <herve.codina@...tlin.com> wrote:  
> > > > The CFG_USB register is located within the system controller.
> > > >
> > > > We need a helper to get the H2MODE value from the CFG_USB register
> > > > without syscon.
> > > >
> > > > Signed-off-by: Herve Codina <herve.codina@...tlin.com>  
> > >  
> > > > --- a/drivers/clk/renesas/r9a06g032-clocks.c
> > > > +++ b/drivers/clk/renesas/r9a06g032-clocks.c
> > > > @@ -25,6 +25,8 @@
> > > >  #include <linux/spinlock.h>
> > > >  #include <dt-bindings/clock/r9a06g032-sysctrl.h>
> > > >
> > > > +#define R9A06G032_SYSCTRL_USB    0x00
> > > > +#define R9A06G032_SYSCTRL_USB_H2MODE  (1<<1)
> > > >  #define R9A06G032_SYSCTRL_DMAMUX 0xA0
> > > >
> > > >  struct r9a06g032_gate {
> > > > @@ -341,6 +343,22 @@ int r9a06g032_sysctrl_set_dmamux(u32 mask, u32 val)
> > > >  }
> > > >  EXPORT_SYMBOL_GPL(r9a06g032_sysctrl_set_dmamux);
> > > >
> > > > +
> > > > +/* Exported helper to get the H2MODE bit from USB register */
> > > > +int r9a06g032_sysctrl_get_usb_h2mode(bool *h2mode)
> > > > +{
> > > > +       u32 usb;
> > > > +
> > > > +       if (!sysctrl_priv)
> > > > +               return -EPROBE_DEFER;
> > > > +
> > > > +       usb = readl(sysctrl_priv->reg + R9A06G032_SYSCTRL_USB);
> > > > +       *h2mode = (usb & R9A06G032_SYSCTRL_USB_H2MODE) ? true : false;
> > > > +
> > > > +       return 0;  
> > >
> > > Perhaps not pass *h2mode, but just return USB_ROLE_{HOST,DEVICE}
> > > (enum usb_role in <linux/usb/role.h>), or a negative error code?  
> >
> > Yes, good idea.
> > I will also rename the function :
> >   enum usb_role r9a06g032_sysctrl_get_usb_role(void);
> >
> > Is that ok for you or do you prefer that I keep the previous name ?  
> 
> r9a06g032_sysctrl_get_usb_role() sounds fine!
> But it should return "int", as the return value can be a negative error code,
> too.

All right, I will do that in v2 series.

Thanks,
Hervé

-- 
Hervé Codina, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com